1. Field of the Invention
The present invention relates to a technique for rewriting data on an in-vehicle electronic control unit.
2. Description of Related Art
In an in-vehicle electronic control unit, for example, data such as programs and control parameters stored in a nonvolatile memory, such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash ROM (Read Only Memory), sometimes needs to be rewritten due to functional updating or the like. Therefore, as described in Japanese Laid-Open (Kokai) Patent Application Publication No. 2010-19175, there is proposed a technique in which rewrite data is transmitted wirelessly from a rewriting tool to multiple vehicles to rewrite data on an electronic control unit in each of the vehicles that received the rewrite data.
Among vehicles of different specifications, only part of the data structure in electronic control units may be different, such as a case in which control parameters are different but the program is the same in the electronic control units. Since the conventional technique assumes that the data structure is the same in electronic control units, data in electronic control units having data structures different only in part cannot be rewritten concurrently. Therefore, data rewriting has to be performed on each group of vehicles with electronic control units having a same data structure, resulting in inefficient data rewriting.